Method for providing a hole in the soil as well as a device for applying said method

ABSTRACT

A method and a device for providing a hole in the soil, for example for forming a foundation element, an earth-retaining wall or a water-retaining wall or the like in the soil, wherein a hollow pipe open at the lower end is introduced into the soil and the earth penetrated into the pipe is removed from the pipe. According to the invention the removal of the earth from the pipe is effected by a pressure fluid which is supplied to the pipe near the lower end of the pipe, and which forces the earth in the pipe upwards as a column.

United States Patent Inventor Jacob Kroon Gouda, Netherlands Appl. No.855,528

Filed Sept. 5, 1969 Patented Aug. 17, 1971 Assignee N.V. Tot AannemingVan Werken Voorheen 11.,1. Nederhorst Gouda, Netherlands Priority Sept.5. 1968 i Netherlands METHOD FOR PROVIDING A HOLE IN THE SOIL AS WELL ASA DEVICE FOR APPLYING SAID METHOD 20 Claims, 7 Drawing Figs.

US. Cl 175/20, 17 5/60, 175/422 lnt. Cl E21b 11/02, E21b 49/00 Field ofSearch 175/65, 60, 422, 20, 215

Primary Examiner-James A. Lcppink Attorney-Waters, Roditi, Schwartz andNissen ABSTRACT: A method and a device for providing a hole in the soil,for example for forming a foundation element, an earth-retaining wall ora water-retaining wall or the like in the soil, wherein a hollow pipeopen at the lower end is introduced into the soil and the earthpenetrated into the pipe is removed from the pipe.

According to the invention the removal of the earth from the pipe iseffected by a pressure fluid which is supplied to the pipe near thelower end of the pipe, and which forces the earth in the pipe upwards asa column.

PATENTEU m1 1 m1 SHEET 1 UF 3 h an 1 :1 l u l SHEET 2 UF 3 PATENTEU AUG]7 I97! METHOD FOR PROVIDING A HOLE IN THE SOIL AS WELL AS A DEVICE FORAPPLYING SAID METHOD BACKGROUND OF THE INVENTION l This inventionrelates to a method for providing a hole in the soil, for example forforming a foundation element, an earth-retaining wall or awater-retaining wall or the like in the soil, wherein a hollow pipe openat the lower end is introduced into the soil and the earth, whichpenetrates into the pipe is removed from the pipe; as well as to adevice for applying said method.

According to a known method, after the pipe has been introduced into thesoil, the earth which penetrates into the pipe is removed therefrom bymechanical means, for example by means of an auger. However, this israther time consuming and requires complicated equipment, furthermorethe removed earth requires much space on the building site and theremoval of this earth from the building site is a messy operation.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide a method for providing a hole in the soil which presentsconsiderable advantages over the above-described known method.

According to the invention the removal of the earth from the pipe iseffected by a pressure fluid which is supplied to the pipe near thelower end of the pipe and which forces the earth in the pipe upwards asa column.

Compressed air, pressurized water or other pressurized fluid may be usedas a pressure fluid.

According to the invention the removal of the earth from the pipe iseffected very rapidly, and the clearing of the earth emerging as acolumn at the top of the pipe may be carried out for example bydeflecting this column laterally and dividing the earth into sliceswhich leave the building site by truck or via a conveyor belt.Consequently the space taken up on the site by the earth to be removedis small and the abovedescribed method results in a clean operation.

It is preferred to reduce the friction between the inner wall of thepipe and the earth in the pipe prior to and/or during the time that saidearth is forced upwards. In this way a plug action is prevented at thelower end of the pipe during the introduction of the pipe into the soiland as a result the length of the mass of earth entering the pipe isalways almost equal to the depth of penetration ofthe pipe into thesoil.

In order to reduce the aforesaid friction, the pipe may have a lowercutting edge the inner cross section of which is slightly less than theinner cross section ofthe pipe. I

By correctly shaping the cutting edge, the advantage may be obtainedthat the earth, which is displaced by the pipe in consequence of itswall thickness, must deflect outwards and will be in contact with theouter surface of the pipe, which is of great importance since in thisway the pressure fluid supplied to the pipe is prevented from flowingout of the pipe via its lower end and escaping upwards around the pipe.

In order to reduce the friction between the inner wall of the pipe andthe earth contained in the pipe it is also possible to introduce thepipe into the soil while the pipe is being vibrated and/or to vibratethe pipe during the time that the earth is forced upwards.

Furthermore, this friction may be reduced by supplying a lubricant, suchas for example a bentonite suspension, to the pipe near the lower end ofthe pipe during the introduction of the pipe into the soil, for whichpurpose the supply conduit for the pressure fluid may be used. In thiscase, said lubricant can also be utilized as a pressure fluid andtherefore, when the pipe has reached the required depth in the soil, itis possible to continue atonce the supply thereof but now underincreased pressure.

If it is necessary to form the hole in a highly permeable soil thedanger may arise that the pressure of the pressure fluid supplied to thepipe near its lower end penetrates into the earth contained in the pipe,and consequently the lateral pressure of this earth on the interior ofthe pipe, and therefore the friction between this earth and the interiorof the pipe increases so that the forcing upwards of the earth isconsiderably reduced and may even come to a standstill. In order toprevent this, there may be formed a sealing layer in the lower portionof the pipe, but above the point of supply of the pressure fluid, priorto forcing the earth upwards in the pipe.

This may be done for example by means of chemical injection, as is knownper se for soil hardening so that a hard homogenous sealing layer isobtained.

If a liquid under pressure is used as a pressure fluid, sheetlikesealing elements having a specific gravity which is lower than that ofthe liquid may be added to the liquid, in order to form a sealing layer.These sealing elements will collect and by mutual overlapping willconstitute the sealing layer. It is for example possible to add smallpieces of synthetic foil, such as polyvinyl chloride foil having asurface area of a few cm. to the liquid under pressure.

A further possibility for forming the sealing layer consists insupplying an emulsion to the pipe near its lower end, the carrier ofsaid emulsion filtering out in the earth and the floating substances ofsaid emulsion constituting the sealing layer.

The invention furthermore comprises a device for providing a hole in thesoil by means of the aforedescribed method.

BRIEF DESCRIPTION OF THE DRAWING The invention will be further explainedwith reference to the drawings, wherein:

FIG. 1 is a vertical section of the lower portion of a first embodimentof the device according to the invention for providing a hole in thesoil.

FIG. 2 is a vertical section of the lower portion of a modifiedembodiment of the device for providing a hole in the soil.

FIG. 3-7 show diagrammatically the various processing steps for formingan earth-retaining wall in adjacent holes in the soil which aresuccessively provided with the device according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS At present holes are providedin the soil for many purposes, for example for soil testing, fordrainage or lowering the water level and for forming foundationelements, such as piles or the like, or earth-retaining walls orwater-retaining walls in the soil.

FIG. 1 shows a first embodiment of the device according to the inventionfor providing such holes in the soil. This device comprises a hollowpipe 1, the cross section of which is cylindrical but may have anyshape. The pipe 1 comprises near its lower end at least one, butpreferably several lateral inlet openings 2 each connected to a supplyconduit 3 extending in upward direction immediately outside the pipe 1.

To the lower end of the pipe 1 there is secured, by means of bolts 4, apipe section 5, the enlarged central portion 5' of which abuts againstthe inner wall of the pipe 1. The pipe section 5 further comprises alower portion 5" of reduced thickness, which connects via an exteriorupwardly and outwardly slanting collar 6 to the likewise upwardly andoutwardly slanting lower edge 6' of the pipe I and which ends at thelower end, via an upwardly and outwardly slanting lower edge 7, into acutting edge 8, the inner cross section of which is slightly smallerthan the inner cross section of the pipe I, The pipe section 5 furthercomprises an upper end portion 5 of reduced thickness extending inupward direction from a collar 9, which fits against the inner surfaceof the pipe I and which extends horizontally a small distance below theinlet openings 2.

The upper end portion 5'' defines with the inner surface of the pipe 1an annular space 10, open at the top, into which the inlet openings 2end.

Above the inlet openings 2 a distributor ring 11 is secured in saidannular space 10, said ring 11 fitting externally of the inner surfaceof the pipe 1 and internally ofthe upper end portion 5, said ring 11being provided with a plurality of passages 12 for the pressure fluiddistributed along the periphery. In each of these passages 12 a valve 13has been screwed from the top, said valve being constructed similar to abicycle tire valve and cooperating with a rubber valve tube 14. Thesevalve tubes 14 end at about the same level as the upper end portion 5"of the pipe section 5.

When introducing the pipe 1 into the soil the cutting edge 8 of the pipesection 5 will ensure that the friction between the earth entering thepipe 1 and the inner wall of the pipe 1 is restricted to a minimum.

Furthermore, when driving the pipe 1 into the soil, a lubricant, such asfor instance a bentonite suspension, may be supplied via the supplyconduits 3 to the annular space in the pipe 1, said lubricant passingthrough the valves 13 and bringing about an additional reduction of thefriction between the inner wall of the pipe 1 and the earth enteringthis pipe 1.

After the pipe 1 has been introduced into the soil to a predetermineddepth, a pressure fluid-for which purpose compressed air or a liquidunder pressure may be used-is supplied via the supply conduits 3 to thelower ends ofthe pipe 1 and the earth contained in the pipe 1 is forcedupwards as a column.

At the upper end of the pipe 1, the direction of movement of the risingcolumn of earth may be deflected and the earth may be divided intoslices. Further, removal of this earth from the building site may beeffected for example, by truck of conveyor belt or similar device.

During tests, a pipe 1 having an inner diameter of 488 mm., which hadbeen provided at the lower end with a cutting edge 8 having an innerdiameter of 478 mm. was driven into the earth over a distance of 25 m.in 2 minutes with the aid of a Schenck DR6O vibrator. An ll percentbentonite suspension was thereby supplied as a lubricant via the supplyconduits 3 to the pipe 1 and during the introduction of the pipe 1 about300 liters of said suspension were used.

Immediately after the pipe 1 had been introduced into the soil to theabove-mentioned depth, the supply of the bentonite suspension wascontinued, but now under a higher pressure, and the earth came up as acolumn out of the pipe 1. During the upward movement of this earth, thesupply pressure of the bentonite suspension was gradually reduced thusensuring a practically contact rate of discharge of the column ofearth.

FIG. 2 shows a modified embodiment of the device according to theinvention for providing a hole in the soil. In this embodiment a pipesection 15 having a cutting edge 8 at its lower end is secured to thepipe 1 by means of welding. The lower portion 1 of the pipe 1 has thesame inner cross section as the pipe piece 15, said inner cross sectionbeing slightly less than the cross section of the upper portion 1 of thepipe I. At the transition between the pipe portions 1' and 1'' an innercollar 16 of the pipe 1 slants inwards and downwards. The inlet openings2 are provided immediately above this collar 16 in the pipe I.

A support ring 17 is welded in the pipe portion 1 and has an inwardlyand upwardly slanting upper edge 18 defining together with the collar 16a groove of V-shaped cross section. This groove accommodates an endstrap 19 of a cable 20 extending upwardly at the outside of the pipe 1and passed through a pipe 21 which has been mounted on the outer wall ofthe pipe 1.

After the pipe 1 has been inserted into the soil to the required depth,the upper end of the cable 20 is pulled, whereupon the end strap 19 cutsthrough the column of earth and forms a bottom surface at the earth inthe pipe 1 and the pressure fluid-which subsequently is supplied via thesupply conduits 3 to the pipe lmay immediately apply pressure on saidbottom surface.

FIGS. 3-7 show diagrammatically the forming of an earthretaining wall inholes provided in the soil in the aforedescribed manner.

In FIG. 3 a round pipe 22 has been brought into the soil by vibrationdown to the required depth whereupon the earth penetrated in said pipe22 has been forced upwards by a pressure fluid.

In FIG. 4 a second pipe 23 has been inserted into the soil while beingvibrated, said second pipe having a flat substantially rectangular crosssection and extending with a narrow side to the pipe 22, and the earthwhich penetrated into said pipe 23 may be removed in the mannerdescribed above.

In FIG. 5 a reinforcement has been arranged in the pipe 22 and concretehas been poured whereupon the pipe 22 has been pulled out and undervibration has been driven again into the soil at the other side of thepipe 23, whereafter the earth which has penetrated into the pipe 22 isremoved.

In FIG. 6 a reinforcement has been arranged in the pipe 23 and concretehas been poured, whereafter the pipe 23 has been pulled out and whilebeing vibrated has again been driven into the soil adjacent the pipe 22but at an angle to its previous position whereupon the earth which hasentered the pipe 23 has been removed.

In this way a zigzag-shaped earth-retaining wall (FIG. 7) can be veryrapidly formed in the soil. If the pouring of the concrete is carriedout at such rate that the mortar of each elongated intermediate portionmay merge with the mortar of the adjacent columns, then an excellentwaterproof wall is obtained.

The invention is not restricted to the embodiments shown in the drawingswhich may be varied within the scope of the appended claims.

I claim:

1. A method for forming a hole in the ground comprising verticallyintroducing a hollow pipe which is open at its lower end from thesurface of the earth into the earth to the ultimate depth of the hole,vibrating the pipe during such introduction into the earth, and removingthe earth which has penetrated into the pipe only after the pipe hasreached its ultimate depth by supplying a pressure fluid into said pipenear its lower end to force the earth in said pipe upwards as a solidmass the introduction of the pipe into the earth being achieved solelyby the vibration and in the absence of supply of pressure fluid.

2. A method according to claim 2, comprising reducing the frictionbetween the inner wall of the pipe and the earth contained in the pipe,prior to and/or during the time that said earth is forced upwards.

3. A method according to claim 2, comprising forming the lower end ofthe pipe with a cutting edge, the inner cross sec tion of which isslightly less than the inner cross section of the pipe.

4. A method according to claim 2, comprising vibrating the pipe duringthe time that the earth is forced upwards.

5. A method according to claim 2, comprising introducing a lubricantinto the lower end of the pipe during the introduction ofthe pipe intothe soil.

6. A method according to claim 1 comprising forming a sealing layer inthe lower portion of the pipe above the point of supply of the pressurefluid prior to forcing the earth in the pipe upwards.

7. A method according to claim 6, wherein said sealing layer is formedby chemical injection.

8. A method according to claim 6 comprising supplying an emulsion to thepipe near the lower end of said pipe, the floating substances of saidemulsion constituting the sealing layer.

9. A method according to claim 1, comprising gradually reducing thesupply pressure of the pressure fluid in the period during which theearth is forced upwards.

10. A method according to claim 1, wherein compressed air is used as thepressure fluid.

11. A method according to claim 1, wherein a liquid supplied underpressure is used as the pressure fluid.

12. A method according to claim 11, comprising adding sheetlike sealingelements having a specific gravity lower than that ofthe liquid to saidliquid under pressure.

13. A method according to claim 12, wherein said sealing elements aresmall pieces ofa synthetic foil.

14. A method according to claim 1, wherein an 1 1 percent bentonitesuspension supplied under pressure is used as said pressure fluid.

15. A method according to claim 1, wherein the pipe is raised after theearth has been forced upwards out of the pipe.

16. A device for forming a hole in the soil, said device com prising ahollow pipe having an open lower end and at least one lateral inletopening near said open lower end; a supply conduit means connected tosaid inlet opening for the supply of a pressure fluid thereto and a pipesection secured to the lower end of said pipe and including a cuttingedge, said pipe section having an inner cross section which is slightlyless than the inner cross section of said pipe, said pipe sectionincluding an upper end portion of reduced thickness extending upwardlyin spaced relation from said pipe and defining an annu- 18. A deviceaccording to claim 17, comprising a valve extending in the longitudinaldirection of the pipe mounted in each of said passages, said valvehaving an upper end situated at substantially the same level as the topof the upper end portion of reduced thickness.

19. A device for forming a hole in the soil, said device comprisingahollow pipe having an open lower end and at least one lateral inletopening near said open lower end, a supply conduit means connected tosaid inlet opening for the supply of a pressure fluid thereto, a pipesection secured to the lower end of said pipe and including a lowercutting edge, said pipe section having an inner cross section which isslightly less than the inner cross section of said pipe, and acable'having an end strap supported in the pipe at the level of saidinlet opening, said cable extending upwards outside the pipe.

20. A device according to claim 19, wherein said pipe has an upwardlyand outwardly slanting collar and comprising a support ring mounted inthe pipe and having an inwardly and upwardly slanting upper edge facingsaid collar, said end strap being supported by said upwardly andoutwardly slanting collar of the pipe and said inwardly and upwardlyslanting upper edge of the support ring.

1. A method for forming a hole in the ground comprising verticallyintroducing a hollow pipe which is open at its lower end from thesurface of the earth into the earth to the ultimate depth of the hole,vibrating the pipe during such introduction into the earth, and removingthe earth which has penetrated into the pipe only after the pipe hasreached its ultimate depth by supplying a pressure fluid into said pipenear its lower end to force the earth in said pipe upwards as a solidmass the introduction of the pipe into the earth being achieved solelyby the vibration and in the absence of supply of pressure fluid.
 2. Amethod according to claim 2, comprising reducing the friction betweenthe inner wall of the pipe and the earth contained in the pipe, prior toand/or during the time that said earth is forced upwards.
 3. A methodaccording to claim 2, comprising forming the lower end of the pipe witha cutting edge, the inner cross section of which is slightly less thanthe inner cross section of the pipe.
 4. A method according to claim 2,comprising vibrating the pipe during the time that the earth is forcedupwards.
 5. A method according to claim 2, comprising introducing alubricant into the lower end of the pipe during the introduction of thepipe into the soil.
 6. A method according to claim 1 comprising forminga sealing layer in the lower portion of the pipe above the point ofsupply of the pressure fluid prior to forcing the earth in the pipeupwards.
 7. A method according to claim 6, wherein said sealing layer isformed by chemical injection.
 8. A method according to claim 6comprising supplying an emulsion to the pipe near the lower end of saidpipe, the floating substances of said emulsion constituting the sealinglayer.
 9. A method according to claim 1, comprising gradually reducingthe supply pressure of the pressure fluid in the period during which theearth is forced upwards.
 10. A method according to claim 1, whereincompressed air is used as the pressure fluid.
 11. A method according toclaim 1, wherein a liquid supplied under pressure is used as thepressure fluid.
 12. A method according to claim 11, comprising addingsheetlike sealing elements having a specific gravity lower than that ofthe liquid to said liquid under pressure.
 13. A method according toclaim 12, wherein said sealing elements are small pieces of a syntheticfoil.
 14. A method according to claim 1, wherein an 11 percent bentonitesuspension supplied under pressure is used as said pressure fluid.
 15. Amethod according to claim 1, wherein the pipe is raised after the earthhas been forced upwards out of the pipe.
 16. A device for forming a holein the soil, said device comprising a hollow pipe having an open lowerend and at least one lateral inlet opening near said open lower end; asupply conduit means connected to said inlet opening for the supply of apressure fluid thereto and a pipe section secured to the lower end ofsaid pipe and including a cutting edge, said pipe section having aninner cross section which is slightly less than the inner cross sectionof said pipe, said pipe section including an upper end portion ofreduced thickness extending upwardly in spaced relation from said pipeand defining an annular space with said hollow pipe which is open at thetop of said upper end portion, said pipe section including a collarbelow the juncture with said upper end portion, said collar being incontact with the hollow pipe and disposed a small distance below saidinlet opening.
 17. A device according to claim 16 comprising adistributor ring mounted in said annular space above the inlet openingand provided with a plurality of passages for the pressure fluiddistributed along the periphery of the ring.
 18. A device according toclaim 17, comprising a valve extending in the longitudinal direction ofthe pipe mounted in each of said passages, said valve having an upperend situated at substantially the same level as the top of the upper endportion of reduced thickness.
 19. A device for forming a hole in thesoil, said device comprising a hollow pipe having an open lower end andat least one lateral inlet opening near said open lower end, a supplyconduit means connected to said inlet opening for the supply of apressure fluid thereto, a pipe section secured to the lower end of saidpipe and including a lower cutting edge, said pipe section having aninner cross section which is slightly less than the inner cross sectionof said pipe, and a cable having an end strap supported in the pipe atthe level of said inlet opening, said cable extending upwards outsidethe pipe.
 20. A device according to claim 19, wherein said pipe has anupwardly and outwardly slanting collar and comprising a support ringmounted in the pipe and having an inwardly and upwardly slanting upperedge facing said collar, said end strap being supported by said upwardlyand outwardly slanting collar of the pipe and said inwardly and upwardlyslanting upper edge of the support ring.